I have a 3yr old ger.shepx.I rercently discovered a lump on his head. What I thought was a lump feels more like fluid.It,s about the size of 1/2 golf ball just to the right of the peak point of his skull. It can be noticed when he looks at me,even from a distanc. He also seems to have lost some weight (in the last 3 weeks) lump was noticed last week.Appetite normal,active as usual. Thank you